People always try to detain the wonderful memories and the impressive grand sight via a camera, especially while the tempo of life is rapidly increasing. The digital camera needs no films and the user could review the pictures easily, so that the traditional camera is gradually superseded by the digital camera. In addition, since the computer technologies have been improved quickly, the computer has become a prerequisite equipment in the modern life and its powerful functions have brought us with lots of convenience and wonderful experiences.
Although the pictures stored in the digital camera could be reviewed with a display without the developing and printing steps, it is sometime still necessary to print out the pictures. If someone needs to print pictures out from the digital camera, he always needs to use the exclusive printer or connects the digital camera to a computer and then uses a common printer connected with the computer. Nevertheless, the feeding spool (and/or the take-up spool) of the ribbon cassette of the photo printer and the common printer could rotate in two-way, that is, the feeding spool (the supplying portion) and the take-up spool (the collection portion) are rotated in normal and reverse directions in response to reciprocal movement of the carriage. During the operation of the printers, if the ribbon is forced, it is possible that the used ribbon collected in the collection portion of the ribbon cassette would be rolled back and then be used again. In such a case, the printing quality of the picture would become really bad.
Please refer to FIG. 1, which is a diagram showing a ribbon cassette structure in the prior art. As illustrated in FIG. 1, the conventional ribbon cassette structure 1 includes a supplying portion 11 and a collection portion 12. The supplying portion 11 has a supplying roller 111 and the collection portion 12 has a collection roller 121. Both the supplying roller 111 and the collection roller 121 could rotate in two ways. Therefore, when the ribbon 13 is forced, the used ribbon 13 on the collection roller 121 might be rolled back to the supplying roller 111 and the printing quality of the following operation of printing would become bad. In order to overcome the defects resulting from the collection roller 121 capable of rotating in two ways, it might be a solution to design a torsion controller to control the rotating direction of the collection roller 121. Nevertheless, within the trends of the simplicity, compactness and easy-carrying, the dimensions of the conventional printers or photo printers have become smaller and the free spaces therein are limited. Due to the miniaturizations of the printers or photo printers, it would not be a good solution to add a torsion controller into the compact printers or photo printers to control the rotating direction of the collection roller 121. Furthermore, it would increase the cost of the printers or photo printers if a torsion controller is added. As above, it does not meet the current demand to add a torsion controller into the conventional printers or photo printers.